The symptom and sign which indicate placenta previa here is Pinless vaginal bleeding.
Placenta previa is a condition where the placenta is covering the cervix or it is attached close to the cervix.
In various times of pregnancy, bleeding may occur. It can not be a serious complication. The cause of the bleeding may depend on the amount of pain or the time of bleeding in pregnancy.
In the first trimester, bleeding may occur and may be due to ectopic pregnancy, miscarriage, implantation of the placenta in the uterus or infection.
Bleeding in late pregnancy lets say twenty weeks can be due to placenta previa or placental abruption.
Answer:
Extrinsic regulatory mechanisms are external and depend on the firing of some factor outside the population itself. Among them are interspecific competition, food and space restrictions, very strong climatic variations, weathering and inharmonious relationships with other populations (parasitism and predatism).
Good examples of interspecific competition appear when rabbits, caves, rats compete for the same plant, or different fish and birds, such as the heron, vie for the same species of smaller fish. This is because these different species keep their populations in the same ecological niche. Competition is often so strong that some species eventually, as one example of an extrinsic homeostatic mechanism overriding an intrinsic homeostatic process is their disappearance or migration to other regions.
In this competition, the presence of adaptations among individuals in the population that promote better food search, speed, vision, and others can make the difference between elimination and survival.
B. because they are not manufactured by the body
Hormones glucagon and insulin are produced in the alpha and beta cells respectively in the Islet of Langerhan in the pancreas. They are involved in the negative feedback system of blood glucose regulation in homeostasis.
GLUCAGON: when there is a low blood glucose concentration, the pancreas detect this and alpha cells produce and release glucagon. Glucagon causes the cells of the body to absorb less glucose from the blood. It also inhibits the process of converting glucose into glycogen (glycogenesis) and cause gluconeogenesis (process of converting amino acids/proteins and lipids/fats into glucose) and glycogenolysis (conversion of glycogen to glucose). Finally, glucagon decreases the rate of respiration so less glucose is required.
INSULIN: when blood glucose is high, insulin is released. Insulin binds with cell surface receptors of cells and activates the enzymes attached to the receptor. The enzymes cause a conformational change in the structural proteins that surround glucose transport protein containing vesicles, causing them to move out of the way so the vesicles migrate up to the cell membrane and glucose transport proteins can fuse with it. Thus, more glucose can be taken in by cells. Insulin also cause glycogenesis (converting glucose into glycogen) and inhibits gluconeogenesis and glycogenolysis.
Basically insulin decreases blood glucose concentration (eg. after eating) and glucagon increases it (eg. skipping breakfast in the morning)
An organism<span> is a living being that has a cellular structure and that can independently perform all physiologic functions necessary for life. In </span>multicellular organisms<span>, including humans, all cells, </span>tissues<span>, </span>organs<span>, and </span>organ<span> systems of the body work together to maintain the life and health of the </span>organism<span>.</span>
